David Letterman couldn’t let the shifting late night lineup pass him by without taking a few stabs at NBC. Dave is no stranger to large late night battles. He told his audience last night about his history with CBS and then moved on to the NBC mess. He referred to Jay Leno as “Big Jaw,” sympathized with Conan O’Brien and Jimmy Fallon and jabbed at Carson Daly. “I have no idea who that is. I have never seen him in my life.”